1664347 has 4 divisors (see below), whose sum is σ = 1689256. Its totient is φ = 1639440.

The previous prime is 1664291. The next prime is 1664353. The reversal of 1664347 is 7434661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1664347 - 2¹⁵ = 1631579 is a prime.

It is a Duffinian number.

1664347 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1664387) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12354 + ... + 12487.

It is an arithmetic number, because the mean of its divisors is an integer number (422314).

2^1664347 is an apocalyptic number.

1664347 is a deficient number, since it is larger than the sum of its proper divisors (24909).

1664347 is an equidigital number, since it uses as much as digits as its factorization.

1664347 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24908.

The product of its digits is 12096, while the sum is 31.

The square root of 1664347 is about 1290.0957328819. The cubic root of 1664347 is about 118.5080792322.

The spelling of 1664347 in words is "one million, six hundred sixty-four thousand, three hundred forty-seven".